Posted: Mon, Jan 13, 2003, 9:57 PM ET (0257 GMT)
A group of American and Canadian astronomers announced the discovery Monday of three moons orbiting the distant gas giant Neptune. The three small moons, none larger than about 40 kilometers in diameter, were discovered using groundbased telescopes in Hawaii and Chile. Multiple images of Neptune and the surrounding space were taken and then added together; the moons revealed themselves as stationary points compared to the streaks formed by the background stars as Neptune moved across the sky. With an apparent magnitude of 25, the moons were too dim to be seen either by previous groundbased searches or by the Voyager 2 spacecraft, which flew by Neptune in August 1989. Eight other moons of Neptune were previously known: six discovered by Voyager 2 and two previously found by telescopes. Larger telescopes and better instruments have driven a glut of new moon discoveries around all four gas giant planets in the last several years, detecting faint moons in distant, irregular orbit. These irregular moons are evidence of collisions between former moons and comets or asteroids, astronomers believe.